join instructions for linux and macos

[blankdots]

• instructions for macos and linux are the same.
• add reference for examples folder

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 69.72%. Comparing base (88c2108) to head (ddb1e90).

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #122 +/- ## ======================================= Coverage 69.72% 69.72% ======================================= Files 6 6 Lines 862 862 ======================================= Hits 601 601 Misses 141 141 Partials 120 120 ``` | [Flag](https://app.codecov.io/gh/neicnordic/crypt4gh/pull/122/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=neicnordic) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/neicnordic/crypt4gh/pull/122/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=neicnordic) | `69.72% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=neicnordic#carryforward-flags-in-the-pull-request-comment) to find out more.

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